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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Mar 2022. Known ransomware use
Windows 10 1507Operating system · Microsoft

CVE-2021-41379

MEDIUM · 5.5 CVSS v3.1 Developing Published 2021-11-10
Fix available
A fix is available. Upgrade to 10.0.10240.19119 / 10.0.14393.4770 or later.
See remediation →
96/100
Remediation priority · Urgent
In the wild Ransomware Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Windows Installer Elevation of Privilege Vulnerability

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · low confidence
Developing — this CVE was published recently and its authoritative NVD entry is still being established, so we're holding a technical summary until the source data settles rather than publish something unreliable. Re-checking after 2026-08-24.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Windows 10 1507Operating system
Affected:< 10.0.10240.19119
Windows 10 1607Operating system
Affected:< 10.0.14393.4770
Windows 10 1809Operating system
Affected:< 10.0.17763.2300
Windows 10 1909Operating system
Affected:< 10.0.18363.1916
Windows 10 2004Operating system
Affected:< 10.0.19041.1348
Windows 10 20h2Operating system
Affected:< 10.0.19042.1348
Windows 10 21h1Operating system
Affected:< 10.0.19043.1348
Windows 11 21h2Operating system
Affected:< 10.0.22000.318

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.0.10240.19119 / 10.0.14393.4770 / 10.0.17763.2300 or later
Fixed in 10.0.10240.1911910.0.14393.477010.0.17763.2300
Vendor patch portal.msrc.microsoft.com →
Recommended fix High confidence

Install the November 2021 security updates (KB5007186 for most versions, or subsequent cumulative updates) to reach the minimum fixed build for your Windows version

  1. Identify the current Windows build version by running 'winver' or 'systeminfo' in Command Prompt
  2. Determine which Windows 10 version (1507, 1607, 1809, 1909, 2004, 20h2, 21h1) or Windows 11 21h2 is installed
  3. Open Windows Update by pressing Windows Key + I and navigating to Update & Security > Windows Update
  4. Click 'Check for updates' and install all available updates
  5. Alternatively, download and install the specific security update for November 2021 (KB5007186 or subsequent cumulative updates) from the Microsoft Update Catalog: https://www.catalog.update.microsoft.com/
  6. Restart the system after installing the update
  7. Verify the installation was successful by checking the installed updates in Control Panel > Programs and Features > View installed updates
  8. Confirm the build number now meets or exceeds the fixed version for your Windows release
Caveat Standard Windows update with no expected breaking changes; as a medium severity elevation of privilege fix, this is a routine security patch

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get it fixed fast

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-41379 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data